Fumitaka Isobe

Cox maze procedure for chronic atrial fibrillation associated with mitral valve disease.

Between April 1992 and October 1993, we combined a modified maze procedure with mitral valve repair (n = 26) or replacement (n = 36) in 62 patients with atrial fibrillation, including 16 patients undergoing reoperation. Associated procedures included aortic valve operation (n = 22), tricuspid annuloplasty (n = 28), atrial plication (n = 10), and others (n = 3). Duration of atrial fibrillation varied from 0.1 to 23 years (average 8.3 +/- 6.4 years), the f-wave voltage ranged from 0 to 0.45 mV (0.16 +/- 0.09 mV), and cardiothoracic ratio varied from 46% to 85% (64% +/- 9%). We modified the maze atriotomies to preserve the sinus node artery and used cryoablation to simplify procedures. Aortic crossclamp time was 142 +/- 25 minutes and cardiopulmonary bypass time 226 +/- 34 minutes. No early or late deaths occurred in a total of 783 patient-months of follow-up. In 52 patients (84%) who regained atrial rhythm, an atrial A-wave was detected in 84% for transtricuspid flow and in 71% for transmitral flow. One patient with sinus rhythm had an episode of transient neurologic ischemia 4 months after mechanical valve implantation. The 10 patients who remained in atrial fibrillation had preoperative fibrillation for a significantly longer time than the rest of the patients with atrial rhythm (14.8 versus 7.2 years p < 0.001) and a larger left atrial dimension (70 versus 58 mm, p < 0.01). Nonetheless, no variable alone could have predicted postoperative rhythm for individual patients. The results suggest that the maze procedure is safe and effective and therefore should be considered for patients with chronic atrial fibrillation undergoing mitral valve operations.

Modified Maze Procedure for Patients With Atrial Fibrillation Undergoing Simultaneous Open Heart Surgery

BACKGROUND Persistent atrial fibrillation (AF) leaves patients symptomatic and at increased risk of thromboembolism even after otherwise successful cardiac surgery. METHODS AND RESULTS To treat AF secondary to cardiac lesions requiring surgery, we combined a modified maze procedure in 101 patients simultaneously undergoing valvular procedures (87), repair of congenital anomalies (12), and other procedures (2), including 24 repeat operations. Duration of AF varied from 0.1 to 30 years (average +/- SD, 8.8 +/- 7.0 years); the f-wave voltage ranged from 0 to 0.45 mV (0.15 +/- 0.09 mV); and cardiothoracic ratio varied from 40% to 99% (63 +/- 9%). Aortic cross-clamp time varied from 75 to 229 minutes (138 +/- 31 minutes), with bypass time ranging from 119 to 326 minutes (217 +/- 42 minutes). There were two early deaths (2%), no late deaths, and one episode of transient neurological ischemic attack in follow-up ranging from 1.0 to 3.1 years, for a total of 190 patient-years. Postoperative rhythms were sinus in 83 patients (82%), junctional in 4 (4%), and persistent AF in 14 (14%), each of whom had mitral valve disease. Patients with other underlying pathology had complete recovery of atrial rhythm. A normal-sized A wave was detected in 88% for transtricuspid flow and in 73% for transmitral flow, suggesting concomitant recovery of atrial contraction. Among 36 patients without mechanical valves, 30 (83%) with atrial rhythm and contraction have been taken off anticoagulation therapy, including 10 who are free of all medication. CONCLUSIONS The results suggest that the combined approach is safe, effective, and indicated in patients who are judged capable of tolerating the procedure and likely to regain atrial rhythm.

The outcome and indications of the cox maze III procedure for chronic atrial fibrillation with mitral valve disease

OBJECTIVE The efficacy of the Cox maze III procedure for chronic atrial fibrillation associated with mitral valve disease is unclear, and so was evaluated in this study. METHODS In 30 patients, we applied the maze III procedure (cut and suture), except for one modification in the case of a left posterior sinus node artery. After dividing the patients into sinus rhythm and atrial fibrillation groups more than 6 months after the operation, we compared various parameters. RESULTS Sinus rhythm was restored in 27 patients (90%). One patient had atrioventricular reentrant tachycardia and needed a pacemaker for sick sinus syndrome (3.3%). The f-wave voltage in lead V1, the preoperative cardiothoracic ratio, the preoperative left atrial systolic dimension, and the duration of atrial fibrillation were 0.23 +/- 0.10 mV, 60.4% +/- 5.2%, 57.4 +/- 8.2 mm, respectively, and 5.1 +/- 4.6 years in the group with sinus rhythm, and were 0.06 +/- 0.05 mV, 77.7% +/- 10.3%, 95.3 +/- 24.0 mm, respectively, and 11.8 +/- 5.5 years in the group with atrial fibrillation. These parameters were all significantly different between the groups. Regarding atrial function, a transmitral flow A wave was detected in 66.7% and a transtricuspid flow A wave in 100%. Only the duration of atrial fibrillation had a significant influence on the restoration of left atrial function. CONCLUSION The maze III procedure was effective for atrial fibrillation associated with mitral valve disease. This procedure should be applied to patients with a cardiothoracic ratio less than 70% and a left atrial systolic dimension less than 80 mm.

Extent of aortopulmonary collateral blood flow as a risk factor for Fontan operations

Between November 1987 and January 1990, 33 patients (tricuspid atresia, 9 patients; mitral atresia, 3; single ventricle, 15; others, 6) underwent Fontan operations. The rate of blood flow returning to the heart during aortic cross-clamping was measured as an indication of the extent of development of aortopulmonary collateral arteries. Percent cardiac return (calculated by dividing the blood flow rate returning to the heart by the cardiopulmonary bypass blood flow rate and expressing the value as a percentage), were 1% to 9%, 7 patients; 10% to 19%, 11; 20% to 29%, 9; 30% to 39%, 4; 40% to 49%, 1; and 50% to 59%, 1 patient. Percent cardiac return showed a significant correlation with postoperative mean systemic venous pressure (r = 0.6, p < 0.01). In those patients in whom percent cardiac return was more than 33%, the mean systemic venous pressure after operation was high (more than 17 mm Hg), and none of these patients survived. To predict percent cardiac return preoperatively, the conventional indices of systemic ventricular volume, pulmonary artery area index, arterial blood oxygen saturation, pulmonary blood flow index, and pulmonary vascular resistance were analyzed. None of these showed significant correlation with percent cardiac return. However, all the patients who had a high percent cardiac return (more than 30%) also had both high arterial blood oxygen saturation (more than 75% in room air) and small pulmonary artery area index (less than 55%). In addition, the age at operation showed good correlation (r = 0.6, p < 0.01) to percent cardiac return.(ABSTRACT TRUNCATED AT 250 WORDS)

Double switch operation in cardiac anomalies with atrioventricular and ventriculoarterial discordance

Since June 1987, 10 of 19 consecutive patients with atrioventricular and ventriculoarterial discordance (average age 4 +/- 2 years) had undergone a double switch operation with the morphologically left ventricle used as a systemic ventricle. There were two combinations of procedures. Atrial switch combined with arterial switch was used in two patients who had a normal pulmonary valve. Atrial switch combined with ventriculoarterial switch by Rastellis procedure was used in eight patients with pulmonary stenosis or atresia and a large ventricular septal defect. One early death and two late deaths have occurred in a postoperative follow-up period of up to 4 years. Subsequent problems were mainly related to the results of atrial switch procedures in patients who had a small atrium because of low pulmonary flow, especially in patients with apicocaval juxtaposition. Our experience suggested that the double switch operation would open a new era of definitive surgical treatment in half of the patients with atrioventricular and ventriculoarterial discordance.

Atrial natriuretic peptide secretion and body fluid balance after bilateral atrial appendectomy by the maze procedure

OBJECTIVES One of the earliest recognized postoperative complications of the maze procedure was the fluid retention in the immediate postoperative period. Routine postoperative administration of diuretics markedly reduces the frequency and severity of the fluid retention. However, the cause of the abnormal fluid balance is still uncertain. METHODS We evaluated 24 patients: 15 patients underwent the maze procedure (maze group) and 9 patients did not (nonmaze group). Blood samples were obtained before and in the time course after operation for atrial natriuretic peptide measurement. To evaluate the influence of atrial natriuretic peptide on the body fluid balance, we also measured the amount of body fluid balance and the total doses of furosemide and dopamine administered after operation. To examine the effect of the maze procedure on atrial natriuretic peptide secretion in chronic phase, we measured plasma atrial natriuretic peptide levels during dynamic exercise in 21 patients who had undergone cardiac operations 2 years before. RESULTS Plasma atrial natriuretic peptide levels in the nonmaze group significantly increased after operation. In contrast, plasma atrial natriuretic peptide levels in the maze group did not increase, and these levels were significantly lower than in the nonmaze group. Although significantly greater doses of furosemide and dopamine were administered to the maze group than to the nonmaze group, the body fluid balance in the maze group was comparable with that in the nonmaze group in the early postoperative period. The response of atrial natriuretic peptide secretion by exercise was significantly attenuated in the maze group (n = 12) compared with the nonmaze group (n = 9) even 2 years after surgery, although there were no significant differences in heart rate or blood pressure during exercise between two groups. CONCLUSIONS These results suggest that the maze procedure attenuates atrial natriuretic peptide secretion in the early postoperative period and persists in chronic phase. This attenuated atrial natriuretic peptide secretion may reduce the ability of the kidneys to handle fluid load early after surgery.

Ten-year experience with the Carpentier-Edwards pericardial xenograft in the tricuspid position.

We reviewed the cases of 66 patients who underwent 67 tricuspid valve replacements with Carpentier-Edwards pericardial xenografts between April 1985 and January 1994. Average patient age at time of operation was 52 years (range 8 to 71 years). Concomitant mitral or aortic valve replacements were performed in 46 patients. There were 10 operative deaths and 6 late deaths. Actuarial survival at 9 years was 75.4% +/- 5.7%. Prosthetic valve endocarditis occurred twice in one patient. Reoperations for tricuspid regurgitation and for concomitant procedures (maze operation and repair for leak of the mitral prosthesis) were performed in two patients. In both cases, examination of the explanted prostheses showed that the tricuspid regurgitation was the result of nonstructural dysfunction caused by fibrous pannus formation on the cusps of the ventricular side. Among the survivors, 47 patients (92%) were in functional class I or II. Prosthetic valve function was studied by color Doppler echocardiography. Among 38 patients, tricuspid regurgitation more than grade 3/4 or transprosthetic gradient more than 5 mm Hg was found in 11. One patient had right heart failure and the others had no symptoms. In 10 years of experience with the Carpentier-Edwards pericardial xenograft, mortality and morbidity after tricuspid valve replacement were satisfactory. Echocardiographic examination revealed subclinical prosthetic dysfunction in 35% of patients who were followed up for longer than 5 years, however, and we believe that these patients should receive careful follow-up.

Comparative Efficacy of the Maze Procedure for Restoration of Atrial Contraction in Patients With and Without Giant Left Atrium Associated With Mitral Valve Disease

OBJECTIVES We sought to determine the effectiveness of the maze procedure for restoring atrial contraction in patients with and without giant left atrium (GLA). BACKGROUND Although the maze procedure has been reported to be effective for refractory atrial fibrillation, it is unknown whether this procedure can restore effective atrial contraction in patients with GLA. METHODS Nineteen patients with and 32 patients without GLA were studied with Doppler echocardiography before and after the maze procedure. Peak velocity and the time-velocity integral of the left ventricular diastolic filling wave during atrial contraction (A wave) and the atrial filling fraction calculated as the ratio of the time-velocity integral of the A wave to that of total diastolic filling were compared between patients with and without GLA. A peak A wave velocity > or =10 cm/s was considered to indicate echocardiographic evidence of effective atrial contraction. RESULTS Regular rhythm with P waves was restored in 10 patients (53%) with and 26 (81%, p < 0.05) without GLA. Four patients (21%) with and 21 patients (66%, p < 0.01) without GLA showed effective atrial contraction by echocardiography. Once atrial contraction was resumed, the degree of atrial contraction was comparable between patients with and without GLA (17+/-5% vs. 17+/-4% for atrial filling fraction at 12 months, respectively). CONCLUSIONS Although most patients without GLA had restored atrial contraction by the maze procedure, it was resumed in fewer patients with GLA. However, once atrial contraction was resumed, the degree of atrial contraction was comparable between patients with and without GLA. Therefore, the maze procedure may be an option in selected patients with GLA.

A New Procedure for Chronic Atrial Fibrillation: Bilateral Appendage-Preserving Maze Procedure

BACKGROUND Atrial transport and atrial natriuretic peptide secretion is severely reduced from normal after the maze III procedure. To improve these factors, we developed a bilateral appendage-preserving maze procedure (BAP-maze). METHODS Forty-six patients with chronic atrial fibrillation who underwent the BAP-maze procedure were compared with 40 patients who underwent the maze III procedure. The ratio of the peak velocity of the A and E waves of transmitral flow (transthoracic pulsed Doppler echocardiography), the left atrial appendage ejection fraction (transesophageal echocardiography), and the atrial natriuretic peptide secretory reserve during treadmill exercise test were measured at 6 months postoperatively. RESULTS Sinus rhythm was restored in 44 patients (95.7%) by the BAP-maze procedure and in 39 patients (97.5%) by the maze III procedure. The ratio of the peak velocity of the A and E waves was 0.52 +/- 0.22 in the BAP-maze group and 0.25 +/- 0.19 in the maze III group (p < 0.0001). The left atrial appendage ejection fraction was 44.7% +/- 11.5%, and the atrial natriuretic peptide secretory reserve was greater in the BAP maze group (p = 0.037). CONCLUSIONS The BAP-maze procedure improved atrial transport and atrial natriuretic peptide secretion as well as simplifying the maze operation, without decreasing its effectiveness against atrial fibrillation.

Rationale of the cox maze procedure for atrial fibrillation during redo mitral valve operations

OBJECTIVE The frequency of reoperation for mitral valve diseases with chronic atrial fibrillation has increased steadily. This study examined the rationale for using the Cox maze operation for atrial fibrillation during redo mitral valve operations. METHODS Between June 1992 and July 1995, we performed the maze procedure in 42 patients as a concomitant operation with redo mitral valve surgery (maze group). Associated procedures were tricuspid valve surgery in 27 patients and aortic valve surgery in 15 patients. The mean age at operation was 57.3 +/- 9.7 years, and the mean interval from the previous operation was 14.3 +/- 10.5 years. The mean follow-up period after the maze procedure was 25.5 +/- 10.8 months. Atrial fibrillation was present at the time of the previous operation in 29 patients (69%). RESULTS Neither hospital death nor late death occurred. Sinus rhythm was regained in 28 patients (67%), and an atrial A-wave was detected in 21 patients (50%) by pulsed Doppler study. Patients in whom sinus rhythm was restored had a shorter history of atrial fibrillation (9.0 +/- 6.0 years vs 15.9 +/- 4.6 years, p = 0.0009), a larger f-wave on lead V1 of the electrocardiogram (0.18 +/- 0.10 mV vs 0.10 +/- 0.08 mV, p = 0.017), and a smaller cardiothoracic ratio (63% +/- 8% vs 67% +/- 5%, p = 0.049) than patients with persistent atrial fibrillation. During the same period, 54 patients underwent mitral valve reoperation without the maze procedure (control group). The aortic crossclamp and cardiopulmonary bypass times were slightly longer (p = 0.048 and p = 0.012) in the maze group (133 +/- 28 minutes and 221 +/- 43 minutes) than in the control group (126 +/- 65 minutes and 197 +/- 78 minutes). There was no significant difference in the amount of chest tube drainage or transfusion between the two groups (890 +/- 510 ml and 2120 +/- 1600 ml, respectively, in the maze group and 840 +/- 480 ml and 2140 +/- 1760 ml, respectively, in the control group). It was not necessary to reopen the chest for bleeding significantly more often in one group than in the other (14% in the maze group and 7% in the control group), and it was possible to operate without transfusion with the same frequency in the two groups (17% in the maze group and 20% in the control group). CONCLUSION These results suggest that the maze procedure should be considered in selected patients who have a high possibility of regaining sinus rhythm during redo mitral valve operations.